The device is the first to run the 10.2 version of the BlackBerry 10 operating system, which features updates to the OS including the BlackBerry Priority Hub, which collects the most important messages across email, social networking and other accounts to give users quicker access to high-priority conversations.

It features a five-inch Super AMOLED display, and a 1.7GHz quad-core processor. In the UK it goes on sale exclusively at department store Selfridges this weekend for £529 without a contract, with other retailers and mobile operators selling it next week.

(Image: Steve Ranger/ZDNet)

The Z30 is the fourth of BlackBerry's BlackBerry 10 devices, following the Z10, Q10 and Q5, and rounds out the BlackBerry 10 portfolio, the company said. Here's a side view showing the volume controls.

BlackBerry said the Z30 is aimed at a prosumer and business audience with an emphasis on productivity.

First impressions are that — as befits a flagship device — it's a return to quality (especially after the cheap-feeling Q5, the last device BlackBerry released). It's a sturdy (but not too heavy) device that feels good in the hand.

It might lack the beloved hard keyboard of the Q10 but, unless you're a Qwerty obsessive, it's all the better for it because no screen real estate is sacrificed as a result. The soft keyboard is very easy to use (clumsy typists will appreciate the frets between the rows of keys), and the predictive text system is elegant too.

The BlackBerry 10 operating system is a good match for the larger screen. The browser worked briskly and the reader mode (which strips out extraneous web formatting) is a neat way of reading online content without having to negotiate your way through overwrought design, although it doesn't work for every page.

Here's the 2880 mAh battery, which BlackBerry says will last for 25 hours of mixed use. It's not a removable battery, however, which may disappoint some, although the Z30 does come with an external battery pack too.

One feature of BlackBerry 10.2 the company is touting is that users can get a preview of any message as it arrives in whatever app their using. For example, if a BBM message arrives, users can reply without leaving the app they have open at the time.

The launch of the Z30 comes during a difficult period for BlackBerry.

It was for a long time the undisputed leader in enterprise smartphones, and enjoyed considerable success for a time in the consumer space too. But since those glory days it has faded dramatically and the BlackBerry 10-based handsets so far haven't been the breakthrough hits the company had hoped.

Earlier this year the company revealed it had formed a special committee to explore options for the business which could include joint ventures, strategic partnerships or alliances, or a sale. Last week the company said it will cut 4,500 staff and refocus on the "enterprise and prosumer market".

The company has now signed a letter of intent agreement under which a consortium led by Fairfax Financial Holdings has offered to acquire the company for $4.7 billion.

Handset sales have disappointed, and the company said it was taking a a pre-tax charge of between $930m and $960m on inventory, primarily attributable to BlackBerry Z10 devices. As a result the company said it would "re-tier" the BlackBerry Z10 to make it available to a broader, entry-level audience.

T-Mobile, the fourth largest mobile provider in the US, said on Wednesday it will stop carrying BlackBerry smartphones in its stores and instead sell them only via its website.

It might lack the beloved hard keyboard of the Q10 but, unless you're a Qwerty obsessive, it's all the better for it because no screen real estate is sacrificed as a result. The soft keyboard is very easy to use (clumsy typists will appreciate the frets between the rows of keys), and the predictive text system is elegant too.

The BlackBerry 10 operating system is a good match for the larger screen. The browser worked briskly and the reader mode (which strips out extraneous web formatting) is a neat way of reading online content without having to negotiate your way through overwrought design, although it doesn't work for every page.